Questions

Language sharply dissociates from spatial cognition inWilliams syndrome.

Sign language perception and production heavily relies onspatial abilities (much more than spoken language).

Does spatial impairment correlate with linguisticimpairment in sign language aphasia?

Spatial cognition is heavily right-lateral whereas spokenlanguage is heavily left-lateral.

Is sign language as left-lateral as spoken language? What is the relationship between sign and gesture?

Why does language “set up shop” whereit does?

Does modality affect the functional neuroanatomy oflanguage?

For example, the M350 localizes in the vicinity ofauditory cortex. Is that just an accident or is it becausethis activity indexes access to representations that areauditory?

Local vs. global hemispheric asymmetries in Deaf signers(Hickok et al. 1998. Brain Lang. 65:276-86)

12 LHD Signers 8 RHD Signers

Two drawing tasks:1. Copy line drawings (BDAE)2. Hierarchical figure task

MM M

M MMMM

M

Spatial cognition in aphasic signers

Trunk Lines

Toe Nails

Eye

Lip

Right Ear Left Ear

Tail

Leg Contour

Chimney

Chimney Line

Window Panes

BushesWindow Sills

Attic Window

Door Knob

Pathway

Double Line on Roof

A of M's

S of J's

G of K's

D of Y's

LHD LHDRHD RHDA. B.

Sign language phonology

Signs are made up of hand shapes

the locations around the body where signs are made

the movements of the hands and arms

orientation of the hands.

SUMMER

UGLY

DRY

A phonological similarity neighborhood in ASL- same hand shape, movement and orientation but differentlocation

ASL morphology

Example of derivational morphology: Adding a rolling movement to the sign “give” (and to most

ASL verb signs) changes the sign’s meaning to “givecontinuously.”

Signers can use different patterns to modify the verb tomean “give to all,” “give to each,” “give to each other”and many other variations.

ASL syntax

No fixed word order (like e.g., Finnish). Grammatical function (subject, object) encoded by

positions in space and direction of movement.

Sign language and iconicity Sign language has more iconicity than spoken language. For

example, many verbs denoting mental states are signed close to thehead.

However, the relationship between signs and their meanings are asconventional as the sound meaning pairs of spoken languages.

Different sign languages such as ASL and BSL mutuallyincomprehensible.

Sign language not “just a loose collection of pantomime-likegestures thrown together willy-nilly”

In fact ability to pantomime does not at all correlate with one’sability to sign…

Corina et al.: Dissociation between Linguistic and NonlinguisticGestural Systems: A Case for Compositionality (1992) Brain andLanguage.

WL 76-year-old congenitally deaf right-handed male.

As a result of stroke, WL has a largefrontotemporoparietal lesion in the left hemisphere.

Brodman’s areas 44 and 45 (Broca’s area) and subsequent whitematter tracts, including arcuate fasciculus, were damaged.

Most of middle and posterior area 22 (Wemicke’s area) was notinvolved in the lesion.

WL’s damage

WL does well on spatial cognition tasks. But WL’s signing is severely impaired. Two main types of errors:

Paraphasias (“mispronounciations”)

Substituting pantomime gestures for signs

“Point to the door and then point to the ceiling”

“Will a brick float on water?”Picture naming

WL shows a dissociation both between language and spatial cognition

and between sign and gesture

Lateralization

Hickok, et al. 1996, Nature, 381:699-702

13 LHD Deaf signers10 RHD Deaf signers

Administered a range of clinical aphasia assessment tests (ASLadapted)

Age of Sign Exposure

Onset Deafness Sex

Handed-ness

Age at Testing Lesion Size/Location Lesion Etiology

Left Lesioned:

LHD01 6 5 m r 81 lg/frontal-parietal Ischemic InfarctLHD02 5 5 f r 66 mod/inf parietal Ischemic InfarctLHD03 0 0 f r 37 lg/frontal Ischemic InfarctLHD04 6 1 f r 51 sm/inf-ant frontal Aneurism Rupture*LHD05 13 0 m r 45 lg/temp-par HematomaLHD06 0 0 m r 77 mod/frontal-temp-par Ischemic InfarctLHD07 0 0 m r 86 sm/sup frontal-parietal Ischemic InfarctLHD08 6 2 f r 64 mod/medial occ Ischemic InfarctLHD09 7 < 1 m r 29 mod/frontal-par Hematoma*LHD10 0 2 f r 79 mod/inf-post frontal Ischemic InfarctLHD11 9 < 1 f r 73 mod/frontal-par Ischemic InfarctLHD12 11 0 f r 79 lg/frontal-temp-par Ischemic InfarctLHD13 4 0 m r 71 mod/inf frontal-par Hematoma

Right Lesioned:

RHD01 12 0 f r 71 lg/front-temp-par Ischemic InfarctRHD02 9 5 m r 82 mod/temp-par Ischemic InfarctRHD03 5 0 m r 60 lg/front-temp-par Ischemic InfarctRHD04 0 0 f r 61 mod/sup front-par Tumor* RHD05 0 n/a f r 38 mod/sup par-occ Hematoma*RHD06 0 0 m r 74 lg/front-temp-par Ischemic InfarctRHD07 11 2 f r 78 mod/frontal-par Ischemic InfarctRHD08 7 <1 m r 74 lg/frontal-temp-par Ischemic InfarctRHD09 6 3 f r 83 mod/temp-par Ischemic InfarctRHD10 0 0 f r 78 mod/temp-par-occ Ischemic Infarct

* = surgical intervention

CorticalSubcortical

Left Hemisphere Damage (n=13) Right Hemisphere Damage (n=8)

Superimposed Lesions

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

MELODIC LINE

PHRASE LENGTH

ARTICULATORY AGILITY

GRAMMATICAL FORM

PARAPHASIA INRUNNING SIGN

SIGN FINDING

SIGN COMPREHENSION

1 2 3 4 5 6 7

Absent

1 sign

always impairedor impossible

none available

present in everyutterance

fluent withoutinformation

Absent(z = -2) (z = -1.5) (z = -1) (z = -.5) (z = 0) (z = +.5) (z = +1)

Normal

limited toshort phrases and

stereotyped expressions

runs throughentire sentence

4 signs 7 signs

normal only infamiliar signsand phrases

never impaired

limited to simpledeclaratives and

stereotypes

normal range

once per minute ofconversation

absent

information proportionalto fluency

exclusivelycontent signs

RATING SCALE PROFILE OF SIGN CHARACTERISTICS

Normal

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

Absent limited toshort phrases and

stereotyped expressions

runs throughentire sentence

MELODIC LINE

PHRASE LENGTH

ARTICULATORY AGILITY

GRAMMATICAL FORM

PARAPHASIA INRUNNING SIGN

SIGN FINDING

SIGN COMPREHENSION

1 2 3 4 5 6 7

Absent

1 sign

always impairedor impossible

none available

present in everyutterance

fluent withoutinformation

Absent(z = -2) (z = -1.5) (z = -1) (z = -.5) (z = 0) (z = +.5)(z = +1)

Normal

limited toshort phrases and

stereotyped expressions

runs throughentire sentence

4 signs 7 signs

normal only infamiliar signsand phrases

never impaired

limited to simpledeclaratives and

stereotypes

normal range

once per minute ofconversation

absent

information proportionalto fluency

exclusivelycontent signs

RATING SCALE PROFILE OF SIGN CHARACTERISTICS

Right Hemisphere Damaged (n=7)

MELODIC LINE

PHRASE LENGTH

ARTICULATORY AGILITY

GRAMMATICAL FORM

PARAPHASIA INRUNNING SIGN

SIGN FINDING

SIGN COMPREHENSION

1 2 3 4 5 6 7

Absent

1 sign

always impairedor impossible

none available

present in everyutterance

fluent withoutinformation

Absent(z = -2) (z = -1.5) (z = -1) (z = -.5) (z = 0) (z = +.5)(z = +1)

Normal

limited toshort phrases and

stereotyped expressions

runs throughentire sentence

4 signs 7 signs

normal only infamiliar signsand phrases

never impaired

limited to simpledeclaratives and

stereotypes

normal range

once per minute ofconversation

absent

information proportionalto fluency

exclusivelycontent signs

RATING SCALE PROFILE OF SIGN CHARACTERISTICS

Left Hemisphere Damaged (n=10)

11 LHD Deaf signers 8 RHD Deaf signers

Three ASL comprehension measures1. Single sign-to-picture matching (BDAE)2. Simple commands (one clause, one step)3. Complex commands (multi-clause/-step)“touch all the circles except the yellow circle” “put the blackcircle on top of the red square”

Analysis looked at1. Left vs. right hemisphere damage2. Temporal lobe lesioned vs. spared

temporal lobeinvolved

temporal lobespared

0

.2

.4

.6

.8

1

RHDLHD

Prop

ortio

n Co

rrect

Single signs Simple sentences

0

.2

.4

.6

.8

1

RHDLHD

Prop

ortio

n Co

rrect

0

.2

.4

.6

.8

1

RHDLHD

Prop

ortio

n Co

rrect

Complex sentences Lexical access and the comprehensionof simple sentences depends on the lefttemporal lobe.

Comprehension of complex sentencesstill left-dominant and termporal-dominant, but overall more bilateral.

RHD has been associated with discourse-level deficitsin hearing patients.

The same appears to hold in the Deaf signingpopulation

How stable is the left lateralization of signs?E.g., does it matter which hand you’re signing with?

Does it matter which hand you’re signing with?Answer: No.

The neuroanatomy of sign largely consistent with the neuroanatomyof spoken languages, although research is still conducted at arelatively coarse level, i.e., investigating language laterality ingeneral as opposed to the neural bases of specific operations.

Even though the physical properties of signs and spoken words arevery different, what seems to matter for the brain is that they bothencode a form-meaning relationship that then gets “fed” into thecomputational system of language.